Roller mills for grinding cereal products



Jan. 24, 1961 J. 8. BALL ET AL ROLLER MILLS FOR GRINDING CEREAL PRODUCTS Filed June 14, 1957 2 Sheets-Sheet 1 J. 5. BALL ET AL ROLLER MILLS FOR GRINDING CEREAL PRODUCTS Jan. 24, 1961 2 Sheets-Sheet 2 Eiled June 14, 1957 \N\\\ \un \\\\\2\ Inoezzfozv TH.GIJ L652? United States Patent ROLLER MILLS FOR GRINDING CEREAL PRODUCTS John Stephen Ball, Woodsmoor, Stockport, and Thomas Harold Gillett, Cheadle Heath, England, assignors to Henry Simon Limited, Cheadle Heath, England, a Britlsh company Filed June 14, 1957, Ser. No. 665,703

Claims priority, application Great Britain July 13, 1956 4 Claims. (Cl. 241227) This invention relates to roller mills for grinding cereal products and is particularly directed to the feeding of the material to be ground into the nip of the grinding rolls.

In the grinding of materials by roller mills it is usual to cascade the material to be ground as a curtain of even thickness into the nip of the rollers which are rotating in opposite directions at different peripheral speeds, so that the material particles are trapped in the nip and ruptured as they pass between the rollers by the relatively moving roll surfaces, the quantity of material forming the cascaded curtain being limited to the amount which can pass between the rollers at their operational speeds without tending to build up at the approach to the nip.

It is normal experience that although an increase in the operational peripheral speeds of the grinding rolls results in an increased throughput for the machine, the operational efliciency of the machine appears to decline because the rate of throughput increase is disproportionate to the speed-power increase.

The object of our present invention is to provide simple and effective means for enabling the throughput of roller miils to be increased without reducing the operational efficiency of the machine.

By research and experiment we have found that the falling off in the operational efliciency of roller mills with increase of roller peripheral speeds is due to the production by the rollers of a cushioning column of air which flows outwardly from the nip of the rollers and retards the flow of material into the nip. This cushioning column of air increases in intensity with increased roller peripheral speeds, each roller producing its own layer of air and the two layers combining at the nip.

In accordance with our present invention, we provide in cooperation with one or each roller of a pair, a scraper deflector extending across the full length of the roller at a position adjacent to the nip of the rollers on the feed side and coming into contact or close association with its roller, each such scraper interrupting air entrained by the roller peripheral surface and diverting such air so that it does not interfere with the flow of material to the nip of the rollers. The air may be carried off by an exhaustion or similar duct or system.

Each scraper deflector may have a hook like end portion which comes at or adjacent to the roll surface at a point between 15 and 40 rotationally in advance of the roll nip, the hook intercepting the air layer on the roller periphery and reversing or otherwise deflecting its direction of movement so that it does not interfere with the material passing to the nip.

We may employ various shapes or arrangements of scraper deflector to ensure that air entrained by the roller peripheries is removed from the latter and diverted where desired.v Such scraper deflectors may form or contain air riiucts through which the air is delivered where desite Patented Jan. 24, 1961 lot:

Referring to the accompanying drawings:

Figure 1 shows a section of a roller mill with one form of our improvement incorporated therein.

Figure 2 is a view similar to Figure l but showing a modification.

In Figure 1, there are two pairs of rollers a, b which rotate in opposite directions at different peripheral speeds, the material to be ground by the rollers being cascaded into the nip between the respective pairs of rollers by feed rollers c, d and a delivery plate e extending beneath the feed rollers. A scraper deflector 'fextends across the full length of each roller a, b at a position adjacent to the nip of said rollers, the hook like end portion g of each scraper coming at or adjacent to its associated roller surface at a point between 15 and 40 rotationally in advance of the roll nip. The said hook portion of each scraper intercepts the air layer on the roller periphery and deflects it from the roller so that it does not interfere with the material passing to the nip.

In the Figure 2 arrangement, each scraper has a part h into which the intercepted air is directed and to which (at one or both ends of the scraper) an exhaustion pipe indicated at i is connected to draw off the air and deliver it where desired.

We may arrange a scraper deexctor in association with one roller of a pair which is preferably the higher speed roller.

What we claim is:

1. A high speed roller mill for grinding cereal products having in combination with at least one roller of a pair of rollers revolving at different speeds, a scraper deflector extending across the full length of the roller at a position adjacent to the nip of the rollers on the feed side of the rollers and being closely associated with the peripheral surface of said at least one roller, said scraper having a hook like end portion which is close to the roller surface at a point between 15 and 40 rotationally in advance of the roller nip, the hook like end portion intercepting and reversing the air layer on the roller periphery.

'2. A high speed roller mill as claimed in claim 1 in which the scraper deflector cooperates with the higher speed roller only of each pair of rollers.

3. A high speed roller mill as claimed in claim 1 in which an exhaustion duct means is operatively associated with said scraper to draw off the air intercepted by the scraper.

4. A high speed roller mill for grinding cereal products having in combination with each roller of a pair of horizontally disposed rollers rotating in .opposite directions, a scraper deflector extending across the entire length of each roller and being closely associated with the peripheral surface of each roller, and each scraper deflector being provided with a hook-like end portion adjacent to the roller surface at a point between 15 and 40 degrees rotationally in advance of the nip of the rollers serving to intercept and reverse the air entrained by the roller peripheral surface so that such air does not interfere with the flow of the material to the nip of the rollers.

References Cited in the file of this patent UNITED STATES PATENTS 248,802 Seek Oct. 25, 1881 294,236 Holt Feb. 26, 1884 1,144,802 Warren June 29, 1915 1,188,323 Richardson June 20, 1916 1,308,007 Forsyth June 24, 1919 2,655,815 McClelland Oct. 20, 1953 FOREIGN PATENTS 46,247 Germany Mar. 19, 1889 

